This proposal is designed to test the hypothesis that an abnormality (primary or secondary) in protein synthesis could account for the accumulation of abnormal collagen in tissues from patients with diabetes mellitus and for the reduced growth potential of fibroblasts derived from diabetic subjects. The studies will be performed on fibroblasts derived from control and diabetic subjects. Using cell synchronization techniques, the major events of the cell cycle will be analyzed for the specific rate limiting step that slows the population doubling time in fibroblasts from diabetic subjects. Fibroblasts from diabetic subjects have an abnormal rate of radioactive protein accumulation. These findings will be extended by measuring rates of protein degradation, amino acid pool sizes and absolute rates of protein synthesis. Using collagen as a marker protein and a recently developed cell-free translation method for collagen mRNA, protein synthesis will be examined in these fibroblasts at the translational and transcriptional level. The level of collagen mRNA and the rate that it is translated (elongation and initiation rates) will be determined. These studies should provide clear avenues for future investigation in the molecular basis of the abnormal biologic features of fibroblasts from diabetic subjects.